Delete blimp/helium and remove references to it from dependent targets

blimp/helium/stream.h

-// Copyright 2016 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef BLIMP_HELIUM_STREAM_H_
-#define BLIMP_HELIUM_STREAM_H_
-
-#include <memory>
-
-#include "base/callback.h"
-#include "blimp/helium/result.h"
-
-namespace blimp {
-namespace helium {
-
-class HeliumMessage;
-
-// Pure virtual interface for HeliumMessage-oriented transport streams.
-// Details about how the helium::Stream is bound to the network layer are
-// handled by subclasses of helium::Stream.
-class Stream {
- public:
-  using ReceiveMessageCallback =
-      base::Callback<void(std::unique_ptr<HeliumMessage>, Result)>;
-
-  virtual ~Stream() = default;
-
-  // Sends |helium_message| over the Stream. |callback| is invoked when the
-  // message is sent (or otherwise moved to the low-level write buffers),
-  // which signals the caller that it is clear to send another message.
-  //
-  // The caller is responsible for ensuring that only one outstanding
-  // SendMessage() call is made at a time.
-  virtual void SendMessage(std::unique_ptr<HeliumMessage> helium_message,
-                           const base::Callback<void(Result)>& callback) = 0;
-
-  // Asynchronously reads a HeliumMessage from the stream.
-  // The caller is responsible for ensuring that only one outstanding
-  // ReceiveMessage() call is made at a time.
-  //
-  // In the event that an error occurred, a null pointer will be passed instead
-  // of a HeliumMessage, with a HeliumResult describing the failure reason.
-  // The HeliumStream object is considered inactive/unusable at this point and
-  // should be discarded by its owner.
-  virtual void ReceiveMessage(const ReceiveMessageCallback& on_receive_cb) = 0;
-};
-
-}  // namespace helium
-}  // namespace blimp
-
-#endif  // BLIMP_HELIUM_STREAM_H_